The research: Of critical importance in understanding the intracellular mechanisms of aminoglycoside nephrotoxicity and the potentiating effects of mild renal ischemia is whether aminoglycosides remain sequestered within the endosomal-lysosomal compartment of renal epithelial cells or are released into the cytoplasm. This question will be examined using several complementary approaches designed to evaluate the intracellular processing of gentamicin including: 1.) immunocytochemical localization of gentamicin internalized across the apical and basolateral membranes of LLC-PK1 cells, and 2.) direct video-microscopy of the dynamic handling of internalized and microinjected FITC labeled gentamicin during normal control conditions and following "chemical ischemia" in LLC-PKl cells.